It was the first time I’ve ever read it and I was surprised how much of it still held true given it’s 25 years old. Some of the specific programming examples are pretty outdated, but the general ideas are as solid as ever!
They mention at one point that Java doesn't have a way to pass a function as a parameter to another function. That was added in Java 8 with lambdas. That's just one off the top of my head.
The only mainstream languages where you can actually pass function references around, without them being sugar for some complex object that the compiler creates are C, C++ and Rust. And it's not trivial to do in Rust.
